Étant donnés (Given: 1. The Waterfall, 2. The Illuminating Gas, French: Étant donnés: 1° la chute d'eau / 2° le gaz d'éclairage.) is Marcel Duchamp's last major art work which surprised most of the art world, who believed he had given up art for competitive chess almost 25 years earlier, following The Bride Stripped Bare by Her Bachelors, Even (also known as The Large Glass).[1] It is a tableau, visible only through a pair of peep holes (one for each eye) in a wooden door, of a nude woman lying on her back with her face hidden and legs spread holding a gas lamp in the air in one hand against a landscape backdrop.

Duchamp worked secretly on the piece from 1946 to 1966 in his Greenwich Village studio.[2] It is composed of an old wooden door, nails, bricks, brass, aluminum sheet, steel binder clips, velvet, leaves, twigs, a female form made of parchment, hair, glass, plastic clothespins, oil paint, linoleum, an assortment of lights, a landscape composed of hand-painted and photographed elements and an electric motor housed in a cookie tin which rotates a perforated disc.[1] The Brazilian sculptor Maria Martins, Duchamp's girlfriend from 1946 to 1951, served as the model for the female figure in the piece, and his second wife, Alexina (Teeny), served as the model for the figure's arm.[3] Duchamp prepared a "Manual of Instructions" in a 4-ring binder explaining and illustrating how to assemble and disassemble the piece.[2]

The piece was created with the intention of having it displayed at the Philadelphia Museum of Art. Anne d'Harnoncourt, a young curator at the time and future director of the museum, orchestrated the acquisition and transfer of the piece to Philadelphia. According to the artist's wishes, it wasn't until 1969, after Duchamp's death in 1968, that Duchamp's widow Alexina Duchamp and his step-son Paul Matisse installed the work at the Philadelphia Museum of Art and revealed the tableau to the public.[4]